When my Google Alerts sounded this past week, I knew that birthright citizenship was again lighting up in the news. My interest in debates over birthright is professional and abiding: I’m a historian who in 2018 published a book, Birthright Citizens, that traced this approach to national belonging from its origins in debates among Black Americans at the start of the 19th century to 1868, when the ratification of the Fourteenth Amendment established that, with a few exceptions, anyone born on U.S. soil is a citizen.

On Monday, Florida Governor Ron DeSantis, looking to advance his presidential campaign, promised to reverse more than a century and a half of law and policy and, as he put it in a statement, “end the idea that children of illegal aliens are entitled to birthright citizenship if they are born in the United States.” A few days later, a spokesperson for another GOP presidential candidate, Nikki Haley, said she “opposes birthright citizenship for those who enter the country illegally,” and the entrepreneur Vivek Ramaswamy’s campaign said he would reform birthright by adding new citizenship requirements. Having lived through more than one such outburst in recent years—the first in 2018, when then-President Donald Trump proposed to do away with birthright—I know that any promise to transform our citizenship scheme is sure to set off a debate.

But what, we should ask, is that debate really about? Why does it keep coming up? When we talk about birthright citizenship, we are talking about democracy—its fundamental component that grants equal status to every person born in this country and affords them all the same rights of citizenship.

Let’s briefly review. Although the 1787 Constitution did not bar Black Americans from citizenship, it also did not plainly state what made any person a citizen. The result was that Black Americans received profoundly uneven treatment before the law; most authorities leaned toward the view that color, with its implied links to slave status, disqualified Black Americans from citizenship. Black activists waged a long campaign arguing that, on the face of the Constitution and as a matter of natural rights, Black people were citizens by virtue of their birth on U.S. soil.

Notoriously, the U.S. Supreme Court, in the 1857 case Dred Scott v. Sandford, concluded that citizenship was beyond the reach of Black Americans; their race disqualified them. During the Civil War and Reconstruction, lawmakers remedied this circumstance: first in an 1862 opinion from Attorney General Edward Bates, then in the Civil Rights Act of 1866, and finally in the first clause of the Fourteenth Amendment, which installed birthright in the Constitution, guaranteeing that Black people and all those born in the United States were citizens.